This invention relates generally to a fluid dispenser and, more particularly, to an arrangement for a nozzle for a fluid dispenser.
Pump assemblies for fluid dispensers are well known. Such pump dispenser includes those invented by the inventor of this present application including those disclosed in U.S. Pat. No. 5,165,577 issued Nov. 24, 1992, U.S. Pat. Nos. 5,282,552; 5,489,044; 5,676,277 and 5,975,360, the disclosures of which are incorporated herein by reference.
These fluid dispensers share a common characteristic with many other fluid dispensers that a fluid is to be dispensed out of an outlet with the outlet forming an open end of a tubular member. In applications of greatest interest to the present invention, the tubular member has its outlet opening downwardly and fluid passing through the tubular member is drawn downwardly by the forces of gravity with a stream of the fluid to become separated from the outlet of the nozzle and to drop downwardly therefrom.
The present inventor has appreciated that a number of difficulties arise with such nozzles particularly when the fluid to be dispensed is viscous.
For example, in dispensing liquid honey, the present inventor has appreciated that a difficulty arises such that after dispensing a quantity of honey, an elongate string of honey is formed which extends continuously from honey in the nozzle.
With other fluids and particularly with those having relatively high surface tension and/or viscosity such as relatively thick hand soaps and with some ketchup and mustard, a difficulty arises that after disposing fluid, fluid can remain in the outlet such that the outlet is partially or fully filled with the fluid. Over time, the fluid can harden, typically at least partially blocking the outlet. Later, dispensing may be prevented or, alternatively, may give rise to any fluid being dispensed being sprayed in an undesired direction through a remaining opening through the outlet past the hardened fluid.
To at least partially overcome these disadvantages of previously known devices, the present invention provides an improved nozzle for a fluid dispenser which has an outlet portion offering increased area for flow therethrough. Preferably, the nozzle comprises an outer tubular member which has an increased cross-section to provide an enlarged outlet. Apertures may be provided to permit air to enter the enlarged portion above the outlet, as in a venturi type relation.
An object of the present invention is to provide a nozzle for a fluid pump which facilitates dispensing viscous fluids such as relatively thick hand soaps, honey, ketchup, mustard and other fluids with a high viscosity.
Another object is to provide a nozzle for a fluid pump for dispensing fluids which have a tendency, typically after extended non-use, to remain adhered to a nozzle outlet and at least partially block the nozzle as by drying and hardening of the fluid in the nozzle outlet with exposure to air.
Another object is to provide a piston for a pump assembly which piston is adapted to dispense viscous fluids and may be formed as a unitary piece of plastic for ease of disposal.
Accordingly, in one aspect, the present invention provides a nozzle for dispensing fluid, the nozzle including an inner tubular portion of a first cross-sectional area and an outer tubular portion of a second cross-sectional area, the inner tubular portion opening into the outer tubular portion and the outer tubular portion having an outlet, wherein fluid passes through the inner tubular portion into the outer tubular portion and subsequently out of the outer tubular portion via the outlet.